The present invention relates to a program and an information processing method. In particular, the present invention relates to a program and an information processing method which are compatible with two boot methods: autonomous boot for autonomously booting up the program from a ROM incorporated in a CPU or externally connected; and heteronomous boot for heteronomously booting up the program by copying firmware onto a RAM under control of an external host or a debugger, and which can be seamlessly used in development and commercialization without modifying the program.
In recent years, system LSIs (large scale integration) have been incorporated into various apparatuses. The system LSI basically includes a CPU (central processing unit), a memory (for example, ROM (read-only memory) and RAM (random-access memory)), and an I/O (input/output) unit, which are integrated in a single LSI chip.
As mentioned above, the system LSIs are incorporated into various apparatuses. For example, they are incorporated into home electrical appliances, audio-video equipment, office-automation equipment, industrial apparatuses, and automobiles, and are used for controlling the systems, networks, and user interfaces therein. The function to be provided in each system LSI differs depending on its use, and thus respective system LSIs have characteristics for particular applications. Therefore, numerous types of system LSIs have been developed for satisfying various requirements.
Also, high-performance system LSIs have been manufactured. In this type of system LSI, a versatile high-performance CPU core, a memory, a versatile I/O unit, and peripheral circuits are combined into one chip, and the system can be expanded by attaching an external memory and an I/O unit thereto.
In any type of system LSI, a versatile circuit function, such as parallel I/O; serial I/O; input port with comparator, counter/timer; A/D (analog/digital) converter; DMA (direct memory access) controller; interrupt controller; and bus controller, and an application-specific peripheral-circuit function, such as PWM (pulse width modulation) controller; stepping-motor controller; liquid-crystal display controller; and DTMF (dial tone multi frequency) circuit, are integrated in one chip together with a CPU and a memory as necessary.
Compared with a board computer, which is formed by combining a CPU chip, a memory chip, and a plurality of peripheral circuit chips on a wiring board, the system LSI is more useful for realizing a compact and inexpensive apparatus. Therefore, the system LSI is often used.
The storage of a program required for operating the system LSI is disclosed in Japanese Unexamined Patent Application Publication No. 5-257696.
In a system LSI, a program boots up by autonomous boot from a ROM either incorporated in a CPU or externally connected, or by heteronomous boot by copying firmware onto a RAM under the control of an external host or a debugger. If the design including the boot method is changed at the development and commercialization of the system LSI, verification and performance evaluation must be performed again.